Light emitting device and method for manufacturing same

ABSTRACT

A method for manufacturing a light emitting device includes: forming a multilayer body including a light emitting layer so that a first surface thereof is adjacent to a first surface side of a translucent substrate; forming a dielectric film on a second surface side opposite to the first surface of the multilayer body, the dielectric film having a first and second openings on a p-side electrode and an n-side electrode provided on the second surface; forming a seed metal on the dielectric film and an exposed surface of the first and second openings; forming a p-side metal interconnect layer and an n-side metal interconnect layer on the seed metal; separating the seed metal into a p-side seed metal and an n-side seed metal by removing a part of the seed metal, which is provided between the p-side metal interconnect layer and the n-side metal interconnect layer; and forming a resin in a space from which the seed metal is removed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefits of priority fromthe prior Japanese Patent Application No. 2008-316752, filed on Dec. 12,2008; the entire contents of which are incorporated herein by reference.

BACKGROUND

Light emitting devices capable of emitting visible and white light areexpanding their applications to, for example, illumination devices,display devices, and backlight sources for image display devices.

In these applications, there is a growing demand for downsizing. In thiscontext, downsizing of electronic devices has been facilitated by an SMD(surface-mounted device) light emitting device in which a light emittingelement chip is bonded onto a lead frame and resin-molded.

To replace fluorescent lamps and incandescent bulbs by illuminationdevices based on semiconductor light emitting devices having low powerloss, it is necessary to enhance mass productivity and reduce cost.

JP-A-2006-128625 (Kokai) discloses an example technique for furtherdownsizing. In this example, a light emitting element chip is flip-chipconnected to an interconnect layer provided on a transparent substrateso as to be externally driven through a columnar electrode and a ball.On the transparent substrate, the light emitting element chip and thecolumnar electrode are covered with a sealant.

However, this example needs the interconnect layer and the columnarelectrode for bonding the light emitting element chip onto thetransparent substrate with high positional accuracy, and is insufficientto meet the requirements for downsizing and mass productivity.

SUMMARY

According to an aspect of the invention, there is provided a method formanufacturing a light emitting device, including: forming a multilayerbody including a light emitting layer so that a first surface thereof isadjacent to a first surface side of a translucent substrate; forming adielectric film on a second surface side opposite to the first surfaceof the multilayer body, the dielectric film having a first and secondopenings on a p-side electrode and an n-side electrode provided on thesecond surface; forming a seed metal on the dielectric film and anexposed surface of the first and second openings; forming a p-side metalinterconnect layer and an n-side metal interconnect layer on the seedmetal; separating the seed metal into a p-side seed metal and an n-sideseed metal by removing a part of the seed metal, which is providedbetween the p-side metal interconnect layer and the n-side metalinterconnect layer; and forming a resin in a space from which the seedmetal is removed.

According to another aspect of the invention, there is provided a methodfor manufacturing a light emitting device, including: forming a lightemitting element by forming a multilayer body including a light emittinglayer so that a first surface thereof is adjacent to a first surface ofa translucent substrate, and by forming a p-side electrode and an n-sideelectrode on the multilayer body, the first surface of the translucentsubstrate including a groove which surrounds the multilayer body;forming a dielectric film on the second surface side, the dielectricfilm having a first and second openings on the p-side electrode and then-side electrode; forming a seed metal on the dielectric film and anexposed surface of the first and second openings; forming a p-side metalinterconnect layer and an n-side metal interconnect layer on the seedmetal; forming a p-side metal pillar and an n-side metal pillar on thep-side metal interconnect layer and the n-side metal interconnect layer,respectively; separating the seed metal into a p-side seed metal and ann-side seed metal by removing a part of the seed metal, which isprovided between the p-side metal interconnect layer and the n-sidemetal interconnect layer; forming a resin in a space from which the seedmetal is removed; and grinding the translucent substrate from a secondsurface opposite to the first surface so as to reach a bottom surface ofthe groove.

According to another aspect of the invention, there is provided a lightemitting device including: a multilayer body having a first surface anda second surface opposite to the first surface and including a lightemitting layer; a p-side electrode and an n-side electrode provided onthe second surface of the multilayer body; a dielectric film havingopenings to which the p-side electrode and the n-side electrode areexposed; a p-side extraction electrode including a p-side seed metalprovided on the p-side electrode and a p-side metal interconnect layerprovided on the p-side seed metal; an n-side extraction electrodeincluding an n-side seed metal provided on the n-side electrode and ann-side metal interconnect layer provided on the n-side seed metal; and aresin layer provided around the p-side extraction electrode and then-side extraction electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C are schematic views of a light emitting device accordingto a first embodiment;

FIGS. 2A and 2B are schematic cross-sectional views of variations of thefirst embodiment;

FIGS. 3A to 3D are process cross-sectional views of a light emittingdevice according to the first embodiment;

FIGS. 4A to 4C are process cross-sectional views of a light emittingdevice according to the first embodiment;

FIGS. 5A to 5D are process cross-sectional views of a light emittingdevice according to the first embodiment;

FIGS. 6A to 6D are schematic views of a light emitting device accordingto a second embodiment;

FIGS. 7A to 7E are process cross-sectional views of a light emittingdevice according to the second embodiment;

FIGS. 8A to 8C are process cross-sectional views of a manufacturingmethod of a first variation of the second embodiment;

FIGS. 9A to 9F are process cross-sectional views showing a method forforming a lens;

FIGS. 10A to 10C are process cross-sectional views showing anotherexample method for forming a lens;

FIGS. 11A to 11D are process cross-sectional views of a manufacturingmethod of a second variation of the second embodiment;

FIGS. 12A to 12E are process cross-sectional views of a method formanufacturing a light emitting device according to a third embodiment;

FIGS. 13A to 13D are process cross-sectional views of a manufacturingmethod of a variation of the third embodiment;

FIGS. 14A to 14C are schematic views of a light emitting device having aconvex lens or a concave lens;

FIGS. 15A to 15C are schematic views of variations of a lens;

FIGS. 16A and 16B are schematic views of a light emitting deviceaccording to a fourth embodiment;

FIGS. 17A to 17E are process cross-sectional views of a manufacturingmethod of a variation of the fourth embodiment;

FIGS. 18A and 18B are process cross-sectional views of a manufacturingmethod of a variation of the fourth embodiment;

FIGS. 19A and 19B are schematic views showing variations of the patternof a metal interconnect layer; and

FIGS. 20A to 20D are schematic plan views showing variations of anelectrode pattern.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention will now be described with reference to thedrawings.

FIG. 1A is a schematic cross-sectional view of a light emitting deviceaccording to a first embodiment of the invention, and FIG. 1B is abottom view of the light emitting device in FIG. 1A.

In FIGS. 1A and 1B, a multilayer body 12 has an upper layer 12 aincluding a light emitting layer 12 e, and a lower layer 12 b, and has afirst surface 12 c which is exposed, and a second surface 12 d on theopposite side. The upper layer 12 a may include a p-type cladding layer,a light emitting layer 12 e, and an n-type cladding layer. The lowerlayer 12 b may be of n-type and serve as a lateral path of current.However, the conductivity type is not limited thereto, but may be theopposite conductivity type.

A p-side electrode 14 provided on the surface of the upper layer 12 a ofthe multilayer body 12 is connected to a p-side metal interconnect layer24 a through a p-side seed metal 22 a. Furthermore, an n-side electrode16 is connected to an n-side metal interconnect layer 24 b through ann-side seed metal 22 b. A dielectric film 20 made of an organic orinorganic material is filled between the seed metal 22 a, 22 b and thesecond surface 12 d.

A p-side metal pillar 26 a and an n-side metal pillar 26 b are providedon the p-side metal interconnect layer 24 a and the n-side metalinterconnect layer 24 b, respectively, and surrounded by a (reinforcing)resin 28 so as to expose at least the surface of the metal pillars 26.Even if the multilayer body 12 is thin, its mechanical strength can bemaintained by the metal pillars 26 a, 26 b and the reinforcing resin 28.The metal pillars 26 serve to reduce stress applied to the multilayerbody 12 through mounting terminals.

The metal interconnect layer 24 a, 24 b and the metal pillar 26 a, 26 bcan be made of a material such as copper, gold, nickel, and silver.Among them, copper is more preferable, because it has good thermalconductivity, high migration resistance, and superior adhesion to thedielectric film. Although the following embodiments assume that thematerial of the metal interconnect layer 24 and the metal pillar 26 iscopper, it is understood that the material is not limited to copper.

The p-side seed metal 22 a, the p-side copper interconnect layer 24 a,and the p-side copper pillar 26 a constitute a p-side extractionelectrode which can be connected to the p-side electrode 14 provided inthe multilayer body 12.

Furthermore, the n-side seed metal 22 b, the n-side copper interconnectlayer 24 b, and the n-side copper pillar 26 b constitute an n-sideextraction electrode which can be connected to the n-side electrode 16provided in the multilayer body 12.

In FIGS. 1A and 1B, a diameter of the copper pillar 26 is larger than adiameter of an opening portion of the copper interconnect layer 24 incontact with the p-side electrode 14 or the n-side electrode 16. Here,the shape may be other than a circle, and in that case, the area of thebase of the copper pillar 26 is larger than the area of the openingportion of the copper interconnect layer 24 in contact with the p-sideelectrode 14 or the n-side electrode 16.

As indicated by the block arrow, light from the light emitting layer 12e can be emitted primarily from the first surface 12 c of the multilayerbody 12 in the upward direction of FIG. 1A.

FIGS. 1A and 1B show a light emitting device based on WLP (wafer-levelpackage). That is, one block indicated by the dashed line in FIG. 1Bcorresponds to an individual light emitting device. Such wafer-levelassembly facilitates implementing CSP (chip size package), where thelight emitting device is downsized close to the bare chip size.Furthermore, it may be possible that there is no need to provide asealing resin, which facilitates achieving lower profile. Thus, thisembodiment can be referred to as a WLP light emitting device.

FIG. 1C shows a light emitting device according to a first variation ofthe first embodiment.

A separating portion 12 f is provided in the multilayer body 12. Inseparation process into the individual light emitting device, theseparation portion 12 f facilitates avoiding cracking of GaN or othermaterial, which is thin, hard, and brittle.

FIGS. 2A and 2B are schematic cross-sectional views of a second andthird variation of the first embodiment, respectively.

In the second variation as shown in FIG. 2A, in the case where the lightemitting layer 12 e is made of a nitride semiconductor, the multilayerbody 12 is often crystal-grown on a sapphire or other translucentsubstrate 10, or crystal-grown on a GaAs or other provisional substrateand then transferred onto a translucent substrate 10 by a wafer bondingprocess or the like. FIG. 2A shows a WLP light emitting device with thetranslucent substrate 10 left behind. The substrate in the crystalgrowth process is often as thick as several hundred μm to reducecracking and warpage. In this embodiment, the translucent substrate 10can be thinned by grinding, because the mechanical strength can beincreased by the copper pillar 26 and the filling of the reinforcingresin 28.

The third variation as shown in FIG. 2B uses a thick copper interconnectlayer 24 c, 24 d as an extraction electrode without providing a copperpillar. The thick copper interconnect layer 24 c functions as the p-sidemetal interconnect layer 24 a in FIG. 2A. The thick copper interconnectlayer 24 d functions as the n-side metal interconnect layer 24 b in FIG.2A. This can simplify the structure and manufacturing process.

FIGS. 3A to 3D show the process from the formation of a light emittingelement to the film formation of a seed metal in the manufacturingmethod of the first embodiment.

As shown in FIG. 3A, a multilayer body 12 having a lower layer 12 billustratively including a buffer layer and an n-type layer, and anupper layer 12 a, is formed on a first surface 10 a of a translucentsubstrate 10 illustratively made of sapphire. The first surface 12 c ofthe multilayer body 12 is adjacent to the first surface 10 a of thetranslucent substrate 10. The second surface (dashed line) 12 d of themultilayer body 12 includes the surface of the upper layer 12 a and thesurface of the lower layer 12 b exposed by removal of the upper layer 12a, and thus has a step difference. The lower layer 12 b is provided inan upward position as compared to the upper layer 12 a. The upper orlower is called, if FIG. 3A is upside-down. Generally, the lower layer12 b is grown on the translucent substance 10, and the upper layer 12 ais grown on the lower layer 12 b.

A p-side electrode 14 is formed on the surface of the upper layer 12 a,and an n-side electrode 16 is formed on the surface of the lower layer12 b. The result is as shown in FIG. 3A. FIG. 3B shows the electrodepattern which is a plan view from a bottom side of FIG. 3A. A dielectricfilm 20 is formed so as to cover the p-side electrode 14 and the n-sideelectrode 16, and openings (first opening and second opening) 20 a, 20 bare formed so as to expose part of the p-side electrode 14 and then-side electrode 16, respectively (FIG. 3C). Furthermore, a seed metal22 illustratively made of Ti/Cu is formed by sputtering, for example(FIG. 3D).

Here, for example, the n-side electrode 16 can be a multilayer ofTi/Al/Pt/Au, and the p-side electrode 14 can be a multilayer of Ni/Al(or Ag)/Au. In the p-side electrode 14, sandwiching a high-reflectionfilm illustratively made of Al or Ag facilitates reflecting upward theemission light from the light emitting layer 12 e to extract a highoptical output. Furthermore, because the seed metal 22 is provided, apad made of Au can be omitted.

FIGS. 4A to 4C are process cross-sectional views showing the process forforming copper interconnect layers in the manufacturing method of thefirst embodiment.

For example, a photoresist 40 is patterned on the seed metal 22 (FIG.4A), and the patterned photoresist 40 is used as a mask to selectivelyform copper interconnect layers 24 by electrolytic plating. Thus, copperinterconnect layers 24 a, 24 b separated from each other are formed(FIG. 4B). Preferably, the copper interconnect layers 24 a, 24 b areformed so that the diameter or the area of the base of the copperinterconnect layer 24 a, 24 b is larger than that of the openings 20 a,20 b. Here, the thin seed metal 22 serves as a current path in theelectrolytic plating process. Subsequently, the photoresist 40 isremoved illustratively by ashing, which results in the structure shownin FIG. 4C.

FIGS. 5A to 5D show the process for forming a copper pillar andreinforcing resin in the manufacturing method of the first embodiment.

As shown in FIG. 5A, a thick-film photoresist 42 is patterned to form anopening 42 a on the p-side copper interconnect layer 24 a and an opening42 b on the n-side copper interconnect layer 24 b. Subsequently, ap-side copper pillar 26 a connected to the p-side electrode 14 and ann-side copper pillar 26 b connected to the n-side electrode 16 areformed by electrolytic plating (FIG. 5B). Here again, the thin seedmetal 22 serves as a current path in the electrolytic plating process.If the thickness of the copper pillar 26 is in the range of e.g. 10 toseveral hundred μm, the strength of the light emitting device can bemaintained even when the translucent substrate 10 is separated. Here,alternatively, the openings 42 a, 42 b may be formed in a dielectricfilm.

Then, the photoresist 42 is removed illustratively by ashing, and theexposed region of the seed metal 22 is removed illustratively by wetetching. Thus, the seed metal 22 is separated into a p-side seed metal22 a and an n-side seed metal 22 b (FIG. 5C).

Subsequently, a reinforcing resin 28 is formed around the copper pillar26 a, 26 b to a thickness generally equal to or less than the thicknessof the copper pillar 26 a, 26 b (FIG. 5D). Thus, the WLP light emittingdevice of FIG. 2A is obtained. Furthermore, by removing the translucentsubstrate 10, the WLP light emitting device shown in FIG. 1A isobtained.

Here, the layer made of the resin and metal is flexible, and the metalis formed by plating at near room temperature. Hence, the residualstress occurring with respect to the translucent substrate 10 isrelatively low. In the conventional technique for separating themultilayer body 12 from the translucent substrate 10 at wafer level, forexample, it is bonded to a silicon substrate with a metal layer formedthereon using Au—Sn solder at a high temperature of 300° C. or more, andthen the multilayer body 12 made of GaN is separated by laserirradiation. However, in this conventional technique, the translucentsubstrate and the silicon substrate being different in thermal expansioncoefficient are both rigid, and are bonded together at high temperature.Hence, a high residual stress remains between these substrates.Consequently, when the separation is started by laser irradiation, theresidual stress is locally relieved from the separated portion andunfortunately causes cracks in the thin, brittle multilayer body 12. Incontrast, in this embodiment, the residual stress is low, and themultilayer body 12 is separated in the state of being fixed to aflexible support. Hence, the device can be manufactured at high yieldwithout trouble such as cracking in the multilayer body 12.

Furthermore, this embodiment based on WLP can readily achieve a smalllight emitting device close to the chip size, which is typically severalhundred μm to several mm for the multilayer body 12 made of nitridematerials.

Such a manufacturing method does not require mounting members such as alead frame and ceramic substrate, and can perform the wiring process andsealing process at wafer level. Furthermore, inspection can be performedat wafer level. Hence, the productivity of the manufacturing process canbe enhanced, which consequently facilitates cost reduction.

FIG. 6A is a schematic cross-sectional view of an individual lightemitting device according to a second embodiment of the invention, FIG.6B is a schematic top view, FIG. 6C is a schematic bottom view of thelight emitting device in FIG. 6A, and FIG. 6D is a schematiccross-sectional view of a variation of the second embodiment.

In addition to the structure of the first embodiment shown in FIG. 1A, asolder ball 36 a and a solder ball 36 b are provided on the surface ofthe copper pillar 26 a and the surface of the copper pillar 26 b,respectively, in a BGA (ball grid array) configuration. The material ofthe solder ball 36 is not limited, but can be lead-free by using SnAg,for example.

On the other hand, a phosphor layer 30 is provided to a illustrativelyuniform thickness on the first surface 12 c of the multilayer body 12.The phosphor layer 30 can absorb emission light from the light emittinglayer 12 e and emit wavelength-converted light. Thus, mixed light of theemission light from the light emitting layer 12 e and thewavelength-converted light can be emitted. If the light emitting layer12 e is nitride-based, a white color, warm white color and the like canbe obtained as a mixed color of the blue light, which is the emissionlight, and the yellow light, which is the wavelength-converted lightfrom a yellow phosphor.

In this embodiment, a phosphor layer 30 having a substantially uniformthickness is provided near the light emitting layer 12 e, and emissionlight is injected into the phosphor layer 30 before diverging. Hence,the spread of light of the emission light from the light emitting layeris made close to that of the wavelength-converted light, whichfacilitates reducing color unevenness.

Furthermore, as shown in FIG. 6A, a convex lens 32 illustratively madeof quartz glass can be further provided on the phosphor layer 30 toconverge the mixed light of white or warm white color, for example,which facilitates achieving higher brightness. Furthermore, because theconvex lens 32 is provided near the light emitting layer 12 e withoutthe intermediary of a sealing resin, the size of the lens can bedecreased, which facilitates downsizing the device.

Thus, WLP facilitates downsizing the light emitting device. Furthermore,because the convex lens 32 can be formed in the wafer state, an assemblyprocess with high productivity can be realized, which facilitates costreduction. In this embodiment, the solder ball 36 provided on thesurface of the copper pillar 26 facilitates installation on the mountingsubstrate.

In the variation shown in FIG. 6D, a concave lens 33 is provided insteadof the convex lens 32 so that the emission light can diverge. Forexample, for use as a backlight source and the like, the emission lightneeds to be incident on the side surface of a light guide plate so as tospread along the surface of the light guide plate. The concave lens 33is suitable for this case.

FIGS. 7A to 7E are process cross-sectional views of a method formanufacturing a light emitting device according to the secondembodiment.

FIG. 7A shows a light emitting device (WLP) 5 from which the translucentsubstrate 10 is removed.

A phosphor layer 30 is formed on the first surface 12 c of themultilayer body 12 which is exposed. The phosphor layer 30 can be formedto a thickness in the range from several to several hundred μmillustratively by a sputtering method, an ink-jet method, a method ofapplying a silicone resin mixed with phosphor particles, and a method ofapplying a liquid glass mixed with phosphor particles (FIG. 7B).Subsequently, a convex lens 32 is formed from quartz glass, for example(FIG. 7C), and a solder ball 36 is formed on the surface of the copperpillar 26 (FIG. 7D). Thus, a WLP-based light emitting device iscompleted. Furthermore, dicing is used for separation (FIG. 7E), whichis easy because the translucent substrate 10 is removed. Here, cuttingcan be performed by a method such as mechanical cutting using a diamondblade or the like, cutting by laser irradiation, and cutting byhigh-pressure water.

FIGS. 8A to 8C are process cross-sectional views of a manufacturingmethod of a first variation of the second embodiment.

In the process cross-sectional views of FIGS. 7A to 7E, the lower layer12 b of the multilayer body 12 is continuous along the first surface 10a of the translucent substrate 10. This is because the multilayer body12 made of GaN is separated by laser irradiation more easily if themultilayer body 12 is formed entirely on the wafer. In this case, thewafer including the multilayer body 12 is desirably fixed onto a flattool or jig by vacuum suction, adhesion or the like.

On the other hand, in the first variation, after the translucentsubstrate 10 is separated, the portion of the multilayer body 12 betweenthe light emitting elements is removed illustratively by further laserirradiation while the wafer including the multilayer body 12 is fixed(FIG. 8A). Furthermore, a phosphor layer 30, a convex lens 32, and asolder ball 36 are formed (FIG. 8B), followed by separation (FIG. 8C).Alternatively, the wafer including the multilayer body 12 may be fixedto a jig which can be detached from the laser irradiation apparatus, andthe multilayer body 12 may be separated by a combination ofphotolithography and etching. Because the multilayer body 12, which isrigid and thin, is separated into small size, the risk of cracking inthe multilayer body 12 in the subsequent handling of the wafer issignificantly reduced. Furthermore, also after separation, because themultilayer body 12 is separated into small size, the multilayer body 12is resistant to cracking. Moreover, the package is flexible as a whole,which results in enhancing the reliability of connection points aftermounting. Furthermore, the package has small warpage, which facilitatesmounting. Moreover, it can also be mounted on an object having a curvedsurface.

FIGS. 9A to 9F are process cross-sectional views showing an examplemethod for forming a lens.

A lens material made of quartz glass 60, plastic or the like is formedon the support 62 such as a semiconductor multilayer body and phosphorlayer, and a dot pattern of a mask material such as a photoresist 50 isformed on the lens material (FIG. 9A). Processing with low selectiveratio for the resist is performed stepwise such as the first step (FIG.9B), second step (FIG. 9C), and third step (FIG. 9D). In each step, theportion around the photoresist 50 is sloped while the resist dot patternis reduced by etching.

Hence, after the resist is stripped off, the cross section has a steeperslope downward (FIG. 9E). Then, mirror finishing by isotropic etchingusing CDE (chemical dry etching) or wet etching is performed to smooththe surface, and the lens is completed (FIG. 9F). Thus, a convex orconcave lens can be formed on the light emitting device.

FIGS. 10A to 10C are process cross-sectional views showing anotherexample method for forming a lens.

As shown in FIGS. 10A to 10C, it is also possible to use a imprintprocess. An SOG (spin on glass) 61 or the like, which is liquid andheat-vitrifiable, is applied onto the support 62 illustratively byspincoating (FIG. 10A), and a mold such as a stamper 53, which ispatterned like a lens, is pressed thereto to form a lens shape (FIG.10B). Then, the stamper 53 is stripped off, and the SOG 61 is vitrifiedby heating (FIG. 10C). In this process, the shape of the stamper 53 canbe arbitrarily designed, and hence a lens having any shape can bereadily manufactured.

FIGS. 11A to 11D are process cross-sectional views of a manufacturingmethod of a second variation of the second embodiment.

In this variation, a convex lens 32 is first formed on the first surface12 c of the multilayer body 12 (FIG. 11A), and then a phosphor layer 31is formed on the convex lens 32 (FIG. 11B). Subsequently, a solder ball36 is formed on the surface of the copper pillar 26 (FIG. 11C), and anindividual light emitting device 6 is obtained by separation (FIG. 11D).

In the individual light emitting device 6 of the second embodiment andthe variations associated therewith, the substrate of the WLP-basedlight emitting device is removed. Thus, a light emitting device havinglower profile is provided.

FIGS. 12A to 12E are process cross-sectional views of a method formanufacturing a light emitting device according to a third embodiment.

In the variation of the first embodiment shown in FIG. 2A, the thicknessof the translucent substrate 10 can be reduced by grinding. For example,leaving as much as several ten μm (FIG. 12A) facilitates enhancing themechanical strength as compared with the structure in which thetranslucent substrate 10 is entirely removed. Subsequently, theprocesses of forming a phosphor layer 30 (FIG. 12B), forming a convexlens 32 (FIG. 12C), forming a solder ball 36 (FIG. 12D), and separation(FIG. 12E) are performed.

FIGS. 13A to 13D are process cross-sectional views of a manufacturingmethod of a variation of the third embodiment.

Forming a convex lens 32 as shown in FIG. 13A is followed by forming aphosphor layer 31 (FIG. 13B), forming a solder ball 36 (FIG. 13C), andseparating (FIG. 13D).

In the light emitting device of the third embodiment and its variation,thinning and leaving the translucent substrate 10 facilitates enhancingthe mechanical strength while keeping small thickness.

FIG. 14A is a schematic cross-sectional view of a light emitting devicehaving a convex lens, FIG. 14B is a schematic cross-sectional view of alight emitting device having a concave lens, and FIG. 14C is a top viewof the light emitting device of FIGS. 14A and 14B.

The lens in the first to third embodiment is an array lens. However, theinvention is not limited thereto. It is also possible to use a singlelens as shown in FIG. 14A or 14B. Use of a single lens can simplify theoptical design and manufacturing process.

FIGS. 15A to 15C are schematic views of variations of the lens.

As shown in the plan views of FIGS. 15A and 15B, lenses 32 a, 32 b, 32c, 32 d, 32 e having different sizes may be arranged. The area coveredwith lenses can be increased by placing small lenses in a gap betweenlarge lenses. Furthermore, as shown in the schematic perspective view ofFIG. 15C, a lens 33 a having a rectangular outline may be used.

FIG. 16A is a schematic cross-sectional view of a light emitting deviceaccording to a fourth embodiment, and FIG. 16B is a bottom view thereof.

In this embodiment, adjacent multilayer bodies are spaced from eachother. Patterning is performed so that the first p-side electrode 14 ofthe first multilayer body is connected to the second n-side electrode 16of the second multilayer body adjacent thereto. Furthermore, the seedmetal 22 between the first multilayer body and the second multilayerbody may be left unremoved. Thus, the seed metal 22 and the copperinterconnect layer 24 are connected between the first and second lightemitting elements. That is, the two light emitting elements can beconnected in series. Such series connection facilitates achieving higheroutput. It is understood that the number of series connection is notlimited to two, but series connection with more stages is possible.Furthermore, multilayer bodies adjacent in the direction crossing thejuxtaposing direction of the first and second multilayer bodies can beconnected to each other to provide parallel connection.

In FIGS. 16A and 16B, the seed metal 22 and the copper interconnectlayer 24 are connected among 2×2 light emitting elements. However, the2×2 light emitting elements do not necessarily need to be separated onthe outside thereof. If this configuration continues throughout thewafer, light emitting elements can be cut out in arbitrary units.

FIGS. 17A to 17E, and 18A and 18B are process cross-sectional views of amanufacturing method of a variation of the fourth embodiment.

The translucent substrate 10 may be separated for each light emittingelement. This can realize a reliable structure because the individuallight emitting element is protected by the rigid translucent substrate10. Furthermore, in the manufacturing method therefor, as shown in FIG.17A, a groove 10 c can be formed in the gap of the translucent substrate10 between the light emitting elements from the light emitting elementformation surface 10 a side. The groove 10 c can be formedillustratively before or after the step of forming the light emittingelement, and can be based on a method such as etching, laser processing,and blade cutting. Then, because the rigid translucent substrate 10 isseparated into small size when the translucent substrate 10 is thinlyground later (FIG. 17E), the cracking can be significantly reduced. Inaddition, also in separation into packages, because the portion freefrom the rigid translucent substrate is cut (FIG. 18B), highproductivity and yield can be achieved. Furthermore, also afterseparation, because the translucent substrate 10 and the multilayer body12 are separated into small size, the translucent substrate 10 and themultilayer body 12 are resistant to cracking. Moreover, the package isflexible as a whole, which results in enhancing the reliability ofconnection points after mounting. Furthermore, the package has smallwarpage, which facilitates mounting. Moreover, it can also be mounted onan object having a curved surface.

FIGS. 19A and 19B are schematic views showing a variation of the patternof the copper interconnect layer.

In FIG. 16B, the separating region 21 between the p-side electrode 14and the n-side electrode 16 is linear. Hence, the wafer may crack in theseparating region 21. In contrast, if the separating portion (dashedline) between the p-side electrode 14 and the n-side electrode 16 ismeandered as shown in FIGS. 19A and 19B, the protruding portion of thecopper interconnect layer 24 serves for reinforcement, which facilitatesmaintaining the mechanical strength even if the translucent substrate 10is thinned by grinding. In FIG. 19A, the copper pillars 26 are arrangedin a generally lattice-like configuration. However, it is also possibleto use an arrangement as shown in FIG. 19B. It is understood that thesame effect is achieved also in the configuration where the translucentsubstrate 10 is separated.

FIG. 20A is a schematic plan view of a basic electrode pattern for twolight emitting element chips, and FIGS. 20B to 20D are schematic planviews of its variations.

Light emission occurs in the region where the current flows in thevertical direction of the chip. Hence, a high optical output can beachieved by increasing the area of the upper layer 12 a including thelight emitting layer 12 e. Here, the area of the lower layer 12 bexposed by removal of the upper layer 12 a is an n-type non-emittingregion, and low contact resistance to the n-side electrode 16 is readilyachieved even if the area is small.

It is difficult to decrease the area of the n-side electrode 16 to equalto or below the size of the bump for flip-chip mounting. However, inthis embodiment, even if the area of the n-side electrode 16 isdecreased, the copper interconnect layer 24 can be used for connectionto a wider extraction electrode. If the area of the extraction electrodeconnected to the p-side electrode 14 is generally equal to the size ofthe extraction electrode connected to the n-side electrode 16, thedevice can be mounted on the substrate through the solder ball 36 in abalanced manner.

In FIG. 20B, the upper layer 12 a including the light emitting layer 12e is placed at the center, and the n-type lower layer 12 b is placedtherearound. This can shorten the current supply path. Furthermore,because the light emitting region is located at the center, it can bereadily aligned with the optical axis of the lens.

In FIG. 20C, the lower layer 12 b is exposed at lattice-like positionswhere the n-side electrode 16 is provided, and the p-side electrode 14is provided therearound. This can further shorten the current path.

In FIG. 20D, the p-side electrode 14 is placed at the center, and then-side electrode 16 is placed at four corners therearound. This canfurther increase the light emitting region. Furthermore, because thelight emitting region is located at the center, it can be readilyaligned with the optical axis of the lens.

The first to fourth embodiments and the variations thereof can providelight emitting devices downsized close to the bare chip size. Theselight emitting devices can be widely used in, for example, illuminationdevices, display devices, and backlight sources for image displaydevices.

Furthermore, in the manufacturing method therefor, the assembly andinspection process can be performed at wafer level, which facilitatesachieving high productivity. Hence, cost reduction can be achieved.

The embodiments of the invention have been described with reference tothe drawings. However, the invention is not limited thereto. Thoseskilled in the art can variously modify the size, shape, material,layout and the like of the light emitting element, multilayer body,translucent substrate, seed metal, metal interconnect layer, metalpillar, reinforcing resin, phosphor layer, lens, and electrodeconstituting the embodiments of the invention, and such modificationsare also encompassed within the scope of the invention as long as theydo not depart from the spirit of the invention.

1. A method for manufacturing a light emitting device, comprising:forming a multilayer body including a light emitting layer so that afirst surface thereof is adjacent to a first surface side of atranslucent substrate; forming a dielectric film on a second surfaceside opposite to the first surface of the multilayer body, thedielectric film having a first and second openings on a p-side electrodeand an n-side electrode provided on the second surface; forming a seedmetal on the dielectric film and an exposed surface of the first andsecond openings; forming a p-side metal interconnect layer and an n-sidemetal interconnect layer on the seed metal; separating the seed metalinto a p-side seed metal and an n-side seed metal by removing a part ofthe seed metal, which is provided between the p-side metal interconnectlayer and the n-side metal interconnect layer; and forming a resin in aspace from which the seed metal is removed.
 2. The method according toclaim 1, further comprising: forming a p-side metal pillar and an n-sidemetal pillar on the p-side metal interconnect layer and the n-side metalinterconnect layer, respectively.
 3. The method according to claim 2,wherein the forming a multilayer body includes forming multilayer bodiesspaced from each other.
 4. The method according to claim 2, wherein theforming a p-side metal interconnect layer and an n-side metalinterconnect layer includes forming by electrolytic plating.
 5. Themethod according to claim 2, wherein the forming a p-side metal pillarand an n-side metal pillar includes forming by electrolytic plating. 6.The method according to claim 2, further comprising: forming a lensmaterial on the first surface side of the multilayer body, furtherforming a mask material on the lens material, and then etching the lensmaterial under a condition that the lens material has a lower selectiveratio than the mask material.
 7. The method according to claim 2,further comprising: applying a liquid glass on the first surface side ofthe multilayer body, and forming a lens by mold press.
 8. The methodaccording to claim 2, wherein the forming a multilayer body includesforming a first and second multilayer bodies spaced from and beingadjacent to each other, the forming a p-side metal interconnect layerand an n-side metal interconnect layer includes connectedly forming afirst p-side metal interconnect layer provided on the first multilayerbody side and a second n-side metal interconnect layer provided on thesecond multilayer body side, and the separating the seed metal into ap-side seed metal and an n-side seed metal includes removing the seedmetal exposed between a first n-side metal interconnect layer providedon the first multilayer body side and the first p-side metalinterconnect layer to separate it into a first n-side seed metal and afirst p-side seed metal, and removing the seed metal exposed between asecond p-side metal interconnect layer provided on the second multilayerbody side and the second n-side metal interconnect layer to separate itinto a second p-side seed metal and a second n-side seed metal.
 9. Amethod for manufacturing a light emitting device, comprising: forming alight emitting element by forming a multilayer body including a lightemitting layer so that a first surface thereof is adjacent to a firstsurface of a translucent substrate, and by forming a p-side electrodeand an n-side electrode on the multilayer body, the first surface of thetranslucent substrate including a groove which surrounds the multilayerbody; forming a dielectric film on the second surface side, thedielectric film having a first and second openings on the p-sideelectrode and the n-side electrode; forming a seed metal on thedielectric film and an exposed surface of the first and second openings;forming a p-side metal interconnect layer and an n-side metalinterconnect layer on the seed metal; forming a p-side metal pillar andan n-side metal pillar on the p-side metal interconnect layer and then-side metal interconnect layer, respectively; separating the seed metalinto a p-side seed metal and an n-side seed metal by removing a part ofthe seed metal, which is provided between the p-side metal interconnectlayer and the n-side metal interconnect layer; forming a resin in aspace from which the seed metal is removed; and grinding the translucentsubstrate from a second surface opposite to the first surface so as toreach a bottom surface of the groove.
 10. A light emitting devicecomprising: a multilayer body having a first surface and a secondsurface opposite to the first surface and including a light emittinglayer; a p-side electrode and an n-side electrode provided on the secondsurface of the multilayer body; a dielectric film having openings towhich the p-side electrode and the n-side electrode are exposed; ap-side extraction electrode including a p-side seed metal provided onthe p-side electrode and a p-side metal interconnect layer provided onthe p-side seed metal; an n-side extraction electrode including ann-side seed metal provided on the n-side electrode and an n-side metalinterconnect layer provided on the n-side seed metal; and a resin layerprovided around the p-side extraction electrode and the n-sideextraction electrode.
 11. The light emitting device according to claim10, wherein the p-side extraction electrode further includes a p-sidemetal pillar provided on the p-side metal interconnect layer, and then-side extraction electrode further includes an n-side metal pillarprovided on the n-side metal interconnect layer.
 12. The light emittingdevice according to claim 11, wherein the p-side metal interconnectlayer, the n-side metal interconnect layer, the p-side metal pillar, andthe n-side metal pillar are made of copper.
 13. The light emittingdevice according to claim 11, further comprising: a phosphor layerprovided on the first surface side of the multilayer body and configuredto absorb emission light from the light emitting layer and emitconverted light having a wavelength different from the wavelength of theemission light.
 14. The light emitting device according to claim 13,further comprising: a lens provided on the phosphor layer and configuredto transmit the emission light and the converted light.
 15. The lightemitting device according to claim 13, further comprising: a lensprovided between the multilayer body and the phosphor layer andconfigured to transmit the emission light.
 16. The light emitting deviceaccording to claim 11, wherein one of the p-side electrode and then-side electrode is provided on the non-emitting region of themultilayer body, and an area of the one electrode is smaller than anarea of any of the other electrode and the metal pillar of theextraction electrode provided on the one electrode.
 17. The lightemitting device according to claim 11, further comprising: a p-sidesolder ball and an n-side solder ball provided on the p-side metalpillar and the n-side metal pillar and being generally equal in size.18. The light emitting device according to claim 11, wherein the p-sidemetal interconnect layer and the n-side metal interconnect layer areseparated from each other by a separating region having a meanderedshape in a plan view.
 19. The light emitting device according to claim11, wherein the multilayer body includes a first and second multilayerbodies spaced from and being adjacent to each other, and beingsubstantially equal in composition and shape, and a first p-sideelectrode provided on the first multilayer body side and a second n-sideelectrode provided on the second multilayer body side are connected toeach other.
 20. The light emitting device according to claim 11, whereina surface of the resin is substantially coplanar with a surface of eachof the p-side metal pillar and the n-side metal pillar.